Examine the data below for a stalk of corn:
X: days
Y: height (inches)
(9,5) (12,17) (22,5) (40,6)

Use logarithmic regression to find an equation of the form y = a + b ln(x) to model the data.
a = -76.204
b = 37.673

Using the graphing calculator, estimate to the nearest day how long it will take the corn to reach 6 feet tall: ✔ 51 days

I need help finding out how to get "51 days" as an answer.

I have converted 6 feet into 72 inches, and plugged that in for y to find x (the days) and my equation and work looks like:
72 = -76.204 + 37.673(x)
148.204 = 37.673(x)
3.933958007 = x

The answer is 51 days, and I got 4. Can someone please show me the correct way to solve this equation! I did something wrong. Thank you, and blessings!